Prerequisite
- A Braincube IoT Server
- The application Modbus install (see appsmanager to install new application)
- A PLC using modbus protocol
The node settings
Once the application Modbus installed you will find new nodes in your node palette:
- modbus-read
Modbus read
The modbus read node is designed to help you read data from a PLC using modbus protocol, mainly Schneider PLC.
You can easily drag and drop this node from the palette to your dataflow and start working with it. The first thing to do is to set up the node:
- Connection
- Variables list
To start with this node you will create a new "modbus server" by opening the dropdown menu, chose "Add new modbus server..." and click on the "edit" button. You will then access this page where you have two tabs for the two settings we have to work on:
About the server connection modbus requires :
- Host: an IP Address which is the IP of the PLC you want to connect to
- Unit ID: Unit ID is usefull when you want to request data coming from a slave and not from the master PLC. By default it is 1, but if you need something specific you should take a look at your PLC network.
- Port: 502 is the standard port used by modbus, change it if you use a specific port in your implementation
- Read funtion:
- Holding registers: it is variable stored into your PLC from the program
- Input register: it is data directly representing the physical input of the PLC
- Endianess: Endianness represents the way data is stored into memory blocks. It is important to know it because it will affect the values if you misconfigure it.
Once you set up this you can click on Add, Done, Deploy to save the settings and then come back to this node configuration. You will then be able to check the connection and go to the newt part: Variabe List
The variable list is a list of Type/Address. This list can be created or updated manually or can be uploaded from a text file. In the node documentation you can find everything about the types we can use. To know what addresses to use you must work with the automation department on your side and the person who can extract this list from the program for you.
Here is an example of a list we can have in this modbus connector:
